From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 91BCA278750; Mon, 5 May 2025 22:55:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746485743; cv=none; b=cbDLsTw5srnTz6D0Gk2H3lN0dKx8t7X0IDwtHFenpGlB3ZsST9YbhgAB8dqlg0oXAG2rATnrv2AFp4KlcyjHDpOBJRNBQpzy03ObnXZQZyJ+N1Ps4olPj3tGPChTFG5JVI+eTV/9ghclAhjbwVGFpt27G5Qe+ARDzTKrQ1rK00g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746485743; c=relaxed/simple; bh=4VF94PrXVRjvhxZctZCRwPwMl/OyynMcRvYM0Eb4v2s=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=jAKVpl+zzgqlfYlblA6MnbP4BHwiFwtUqr1SmeeMtn0joxjwFpWvvOuSH6ZVPbhilbo+4WQVUu6Aux8B3PcgRXHTeqyY+y7DDcyfjsHQnpcVOoxseZptsn9mLRNTuVy4QZo9ZMZhtK/FwA7arpUshu/ug7OCEuriuY+QRb8n1Xc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ezKPBSZB; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ezKPBSZB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7FAD3C4CEED; Mon, 5 May 2025 22:55:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1746485743; bh=4VF94PrXVRjvhxZctZCRwPwMl/OyynMcRvYM0Eb4v2s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ezKPBSZBbVwflYqVdXN/UBkXv+SGa/QsydJxoSxv3YJMcgrXZFEtxWyuKkLyXC+e4 S6HGxaVpaOJ6O5ayW44BDSU/R7OHAluqNw3sJS7ZplNg2kIFbxvJpacrfCtUGBHcb1 5A3BX2qTsMBEUT4c8/JST7YS03HpPk+YfnZl4TkN7AqNb8wFNGColYi2AVSXrkJGBZ 5cpj/2LFdKwQXAWd0IP7rqQrR7SK+cpfFShw0wcl276KODFMK1Qt7+uztTOlWF/zE/ ozDYx+K8Zhko4elH1RWwnJcIAic6cmo1PtdhzL9G4RRctJ6KOAmCTctpTtP1lgEpIc jymxOqNdthezg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Viktor Malik , Andrii Nakryiko , Quentin Monnet , Alexei Starovoitov , Sasha Levin , daniel@iogearbox.net, bpf@vger.kernel.org Subject: [PATCH AUTOSEL 6.12 457/486] bpftool: Fix readlink usage in get_fd_type Date: Mon, 5 May 2025 18:38:53 -0400 Message-Id: <20250505223922.2682012-457-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250505223922.2682012-1-sashal@kernel.org> References: <20250505223922.2682012-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.12.26 Content-Transfer-Encoding: 8bit From: Viktor Malik [ Upstream commit 0053f7d39d491b6138d7c526876d13885cbb65f1 ] The `readlink(path, buf, sizeof(buf))` call reads at most sizeof(buf) bytes and *does not* append null-terminator to buf. With respect to that, fix two pieces in get_fd_type: 1. Change the truncation check to contain sizeof(buf) rather than sizeof(path). 2. Append null-terminator to buf. Reported by Coverity. Signed-off-by: Viktor Malik Signed-off-by: Andrii Nakryiko Reviewed-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20250129071857.75182-1-vmalik@redhat.com Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- tools/bpf/bpftool/common.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c index 9b75639434b81..0a764426d9358 100644 --- a/tools/bpf/bpftool/common.c +++ b/tools/bpf/bpftool/common.c @@ -461,10 +461,11 @@ int get_fd_type(int fd) p_err("can't read link type: %s", strerror(errno)); return -1; } - if (n == sizeof(path)) { + if (n == sizeof(buf)) { p_err("can't read link type: path too long!"); return -1; } + buf[n] = '\0'; if (strstr(buf, "bpf-map")) return BPF_OBJ_MAP; -- 2.39.5